The Diagnosis and Recommendation Integrated System for Monitoring Nutrient status of Rice in Lowland Areas in the Vicinity of Satluj River in Punjab

摘要

The Diagnosis and Recommendation Integrated System (DRIS) approach was employed to monitor the nutrient status of rice crop cultivated in lowland areas in the vicinity of Satluj River in district Ludhiana. Standard reference DRIS norms were established for various nutrient ratios obtained from high yield population of rice crop and were further used to compute DRIS indices, which assessed nutrient balance and order of limitation to yield. The DRIS-derived sufficiency ranges for N, P, K, Ca, Mg and Sfrom nutrient indexing survey of rice plants grown on lowland areas were 1.49-2.50,0.14-0.23,0.57-1.11,0.30-0.58,0.13-0.30 and 0.14-0.26%, respectively. The limits for Fe, Mn, Zn and Cu were 64-217, 72-184, 15-24 and 3-6 mg kg~(-1), respectively. On thebasis of sufficiency ranges, 14.50,1.78,11.20 and 0.76% samples were low in N, P, K and S, respectively, from three hundred and ninety-three rice crop fields surveyed. In case of micronutrients, 1.53 and 2.04% samples were low in Mn and Zn, respectively.Validation experiments were carried out in the following year at some selected sites for rice crop on the basis of most required nutrient element by DRIS approach. Soil application of the most required macronutrient elements (N, P, K and S) through their respective fertilizer and micronutrients (Zn, Cu and Mn) through foliar spray of their salts changed their respective order from the most required to their lesser or the least one among the ten nutrient elements and eventually contributed to increase in grain yield of rice except Mn. The DRIS was also validated at some sites where Ca and Mg were identified as the most required nutrient elements. However, application of CaCl_2 or MgCl_2 at these respective locations did not contribute to increase in the grain yield of rice. Thus, DRIS approach, besides diagnosing the deficiency or identification of inadequacy of a certain nutrient element (even if all the ten nutrients are within the sufficiency range), helped in increasing rice yield by application of most required nutrient through fertilizers.